Housing for high-voltage terminals



v Jan. 28, 1930. l F s SMlTH 1,744,929

HOUSING FOR HIGH VOLTAGE TERMINALS- Filed March 1'?. 1922 ATTORNEY 40 practical form, and capable of having readily reenter las. as, ieee NETE@ STATES ibidem@ PATENT @FllQi- .FRANKLIN S. SMITH, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR T THE .PROD- D'CTS PROTECTION CORPORATION, OF NEW YORK, N. Y., A CORPORATION 0F :DELA- WARE HOUSING- FOR HIGH-VOLTAGE TERMINALS .application filed March 17, 1922. Serial No. 544,639.

ln the construction of high voltage terminals, such as that disclosed in my prior Patent #1,703,409, dated Feb. 26, 1929, the terminal construction includes a single slightly tapered tubular member or housing ot suitable dielectric material. rllhis material preferably consists of molded phenolic condensation product, for example, bakelite. These housings are in many cases relatively large, their dimensions or size depending upon the voltage of the apparatus, for instance, an electric transformer, inconnection with which the terminal is used. 'The molding of the housings of the larger dimensions is relatively expensive and dicult in consequence of whichl it is desirable that a construction of housing 4be employed which Vwill permit the employment of relatively small parts.

' @ne of the objects, therefore, of my invention is to provide a high voltage terminal capable of highly edicient action at high volt- 4 ages, of thoroughly practicalconstruction', and embodying a housing consisting'of a plurality of molded sections of a suitable Y material, such as a phenolic condensation product, secured together in a practical and eicient manner, which housing is adapted to l be lilled with gas under pressure greater than atmospheric.`

Another object is to provide a high voltage terminal of inexpensive construction and moreover to provide a construction of the above-mentioned nature capable of meeting,

' in a thoroughly practical and eliicient manner,

the varying conditions imposed thereon by practical use. Another object'is to provide a` high voltage terminal V.of exible construction, capable ofinexpensiveembodiment 1n placedjin assembled relation as many standH ardized sections thereof as are required to withstand the intended voltage, while at the same time avoiding the necessity of a specially constructed terminal to meet desired conditions of use. Another object is to provide a description thereof which follows or will be apparent from such description.

The invention accordingly consists in the features of construction, combinations of elements, and arrangements of parts as will be exemplified in the structure to be hereinafter 50 described and the scope of the application oi which Will be indicated in the following claims.

ln the drawing forming a part ot this specification and in which l have illustrated one form of mechanical embodiment of my inventionj Fig. l is a longitudinal sectional view of a high voltage terminal including a housing embodying my invention and showing a porlo tion of the apparatus to which the terminal is connected; and

Fig. 2 is an enlarged transverse sectional view taken on the line 2 2 of Fig. l

Referring now to the drawing there is l5 shown at l a portion of a casing or an electric transformer provided with a bushing 2 which is secured by Welding within an opening through said casing. The greater portion of said bushing outside of the casing l is externally screw threaded as indicated at 3 to provide means whereby the inner end portion of the section 4 of the terminal housing may be secured thereto. In the construction as shown the housing for the terminal com- 35 prises two additional sections 5 and 6 which may consist ofmolded phenolic condensation product or other suitable dielectric material. These sections are connected together and the joint between the same hermetica-lly sealed by means of metallic bushings 7 and 8. The bushings 7 and 8 are externally screw threaded as indicated and their opposite end portions have screw threaded `connection with internal screw threads adjacent the ends of the sections 4, 5 and 6, as is shown in Fig. l of the drawing. For the purpose of rendering the connections between the sections 4, 5 and 6 and the bushings 2, 7 and 8 and the terminal plug 10 gas pressure tight, a suitable mu cement is interposed between the screw threads of the said bushings and plug and the'said sections.

Although in the construction as shown three sections 4, 5 and 6 of the housing are employed it will be understood that the number of these sections may be increased or diminished as desired.

Secured in the outer end of the outermost section, designated 6 in the present construction, is a terminalplug 10 in which a metallic tube 11 is anchored, the opposite inner end of which projects into the chamber of the casing 1. Said tube is concentric with the bushing 2. A lead wire 12 extends into the said metallic tube 11 'from the inner end thereof and its outer end is likewise anchored within the plug 10 and is also electrically connected with the said tube 11. If the voltage generated by the apparatus should be relatively small, say 20 kv., requiring only a relatively short terminal structure, both of thesections 4 and 5 may be omitted. In such case a bushing 2 of proper size would be employed in the larger end of the section 6. In such case the lengths of the metallic tube 11 and of the lead 12 would be correspondingly decreased.

Each of the sections is provided a short distance from its inner end with an interior shoulder 15 against which the outer ends of the bushings 7 and 8 abut when the said bushings are screwed int-o place therein. The purpose of thus abutting the outer ends of said bushings in these sections is to prevent the turning of the said bushings within said sections when the ends of the adjacent sections are being screwed onto the opposite ends of said bushings. For instance, assume that it is desired to secure the adjacent ends of the sections 4 and 5 to the bushing 7; the said bushing is lirst screwed into the inner end of the section 5 until its outer end abuts against the shoulder 15. Thereafter, the section 5 being held firmly in any suitable manner, the section 4 is screwed onto the outer projecting end portion of the bushing 7. This may be done because the bushing 7 is prevented from turning by reason of the abutting of its outer end against the said shoulder 15.

Although the bushings 7 and 8 have been referred to as metallic, it will be understood that if preferred bushings of non-metallic material may be employed. These bushings 7 and 8 constitute isolated capacities but they do not interfere with the operation of the devlce.

It will be seen that by my invention I have provided a housing constituting a part of a high voltage terminal structure which housing includes a plurality of tubular parts or sections having their adjacent ends secured together in themanner shown or in any other known practical manner which may be preferred, thereby not only decreasing the cost the achievement of many advantages thereof i will be clear from the forego-ing, it might be noted, however, as conducive to a clearer understanding of the various ,features of my invention and of its action in practice that, as will be seen from Figures 1 and 2 of the drawing, the high tension lead or conducting tube 11 is held in substantially a central or concentric relation with respect to the several tubular sections 4, 5 and 6, and with respect to the several bushings, such as 7 and 8, and also with respect to the bushing 2 which is welded to the casing 1 through the wall of which the high tension energy is to be passed and from which the high tension lead or conducting tube 11 is to be insulated. This relation of the several parts, moreover, is achieved by the highly advantageous arrangement whereby, even though the housing made up of the tubular sections has to wit-h1 stand the pressure of the gaseous dielectric, the high tension lead or tube 11 is relieved from having imposed upon it any of the strains or tensions necessary to maintain the tubularsections in fluid tight-relation. The high tension lead or tube 11 will be seen to be free and substantially unsupported at its lower end, as is clearly seen from Figure 1. This above-mentioned advantageous arrangement is of great practical importance since, even though the insulating material, hereinabove mentioned as consisting preferably of bakelite, may have a coeiiicient of expansion different from that of the metal tube or high tension lead 11, the resultant different expansions or contractions of these parts in response to heat changes may freely take place without detrimentally affecting the iuid tight relation of the tubular sections of the housing or the relation, for example, of the lead 11 with respect to the bushing 2. As will be further seen from Figure 1, the

pressure of the gas within t-he housing, exs erted both in an axial direction or lengthwise of the housing and in a radial direction, is resisted or taken up by the built-up housing construction itself and that the high tension conductor or tube 11, depending from the upper end of the housing, does not have .to

take part in resisting the pressure of the gas or in holding the sections or parts together in iiuid tight relation. The permanency of the pressure-tight relation of the several parts of the housing, as well as of its connection to the container 1, is thus assured, a less yexpensive construction achieved than has heretofore been possible, and many troubles and dilhculties avoided, all without interfering with or complicating the teasibility of rapidly and conveniently assembling various sections to provide high voltage ter- 'minals of diderent lengths to meet the requirements of diterent magnitudes of voltages.

lt will thus be seen that there has been provided in this invention a high voltage terminal construction in which the several objects hereinbefore noted, as well as many thoroughly practical advantages are success- 1 housing comprising a plurality ot tubularv sections of solid dielectric material about and spaced from said conducting lead and arranged in end to end relation and dimensioned to withstand the pressure of said dielectric in a radial direction, and a metallic bushing extending across the joint between adjacent ends of any two sections, said bushing being interiorly positioned with respect' to said housing but spaced radially from said conducting lead and adapted to form a fluidtight connection between adjacent sections and to hold adjacent sections in end to end relation lagainst the pressure of said dielectric in an axial direction, the space between said sections and said lead and between said bushing and said lead being filled with said dielectric under pressure. Y `J 2. ln apparatus of the character described, in combination, means `forming a chamber having an opening therein; a high voltage conducting lead extending through said opening and into said means; and means for insulatingly supporting said lead with respect to said first-mentioned means and adapted with the latter to receive a fluid dielectric under relatively high pressure, comprising a housing made up of a plurality of tubular sections of solid dielectric material arranged in end to end relation and dimensioned to withstand the pressure .of said di electric in a radial direction, and a plurality of metallic means for securing one end section to said first-mentioned means, adjacent sections together, and said lead to the other section, in fluid-tight relation, said securing means being adapted to withstand the pressure of said dielectric in an axial direction relative to said sections, said metallic means being disposed within the compass of said housing and those portions of the lead within the housing being spaced from said housing and said metallic means.

3. ln high voltage terminal construction, in combination, a high voltage lead; .an electrically conductive member having a substantially circular opening therein; means for substantially centrally supporting said lead with respect to said opening, said means including a plurality of tubular sections of solid dielectric material arranged in end to end relation, means for securing one of said sections .to said member and adjacent the opening therein, metal-lic means for securing adjacent sections together and disposed within said sections, and means for securing said lead to the end of the section remote from said member, the interior walls of said sections and said metallic means being spaced radially from said lead; and means including a gaseous dielectric under pressure in the space between said lead and lsaid sections and said metallic means for preventinoarcing-over from :said lead to said electrically conductive member by way of said metallic securing means. i

4. ln high voltage terminal construction,

in combination, a high voltage lead; a mem-v ber having an opening therein and through which said lead is to be passed; .a metallic bushing secured to said member; and means for supporting said lead with respect to said bushing, said means including a plurality of tubular sections of solid dielectric material varranged in end to end relation, one of said of said lead in the end'of the section remote from said bushing and holding said lead in spaced relation to the inside wall of said bushing, said sleeve-like member and the side walls of said sections being spaced from said lead; and means including a gaseous dielectric under pressure in the space between said A lead and said sect-ions and said sleeve-like member for preventing arcing-over ,from said lead to said bushing by' way of said sleeve- Alike member.

5. In high voltage terminal construction, in combination, a high voltage lead; a member having an opening therein and through Which said lead is to be passed; a metallic bushing secured to said member; and means for supporting said lead with respect to said bushing, said means including a plurality of tubular sections of solid dieleetric-material arranged in end to end relation, one ofv said sections being secured to said bushing, a metallic sleeve-like member securing adjacent sections together, means mounting one end of said lead in the end of the section remote from said bushing and holding said lead in spaced relation to the inside wall of said bushing, said sleeve-like member and the side walls of said sections being spaced from said lead; a gaseous dielectric under pressure )filling the space between said lead and the side walls of said lsections and between said lead and said sleeve-like member and between said lead and said bushing,the radii of said lead and said bushing beingfpropor'tioned to form a discharge gap adapted to break down upon a predetermined increase in voltage above normal.

6. In high voltage terminal construction, in combination, a high voltage lead; an electrically conductive member having asubstantially circular opening therein; means for substantially centrally supporting said lead with respect to said opening, said means including a plurality of tubular sections of solid dielectric material arranged in end to end relation, means for securing one of said sections to said member and adjacent the `opening therein, metallic means for securing adjacent sections together and disposed within said sections, and means for securing said lead to the end of the section remote from said member, the interior walls of said sections and said metallic means being spaced radially from said lead; and means for, preventing spark-over from said lead to said metallic member by way of said metallic securing means comprising a gaseous dielectric under pressure in the space between said lead and K said sections between said lead and said metallic means, and a conductive member related 4 to said lead'in predetermined dischargey` gap relation and adapted tocause a discharge from said lead upon a predetermined increase in voltage above normal. J

In testimony that I claim the foregoing as my invention, I have hereunto signed my name this 13th dayl of March, Ai D., 1922.

' FRANKLIN S.` SMITH. 

